Wireless Local Area Networks (WLANs), which may be enterprise networks, wireless mesh networks, first-responder networks, home networks, etc., are highly popular and are widely used in commercial as well as residential environments. A main challenge in providing high performance in wireless networks is overcoming variations in wireless channel conditions. Because of the shared medium, the wireless channel quality varies over time due to contention, interference, fading, etc.
In order to provide reliable connectivity and quality of service, a wireless system (e.g., an access point and clients in the WLAN) switches (i.e., changes) the channel it is operating on when the system performance degrades or military radar is detected in UNI-2 band in the current channel. When selecting a new, better channel, the quality of all the other channels is determined by scanning all the other channels. The scanning time is proportional to the number of channels, and the number of channels is very large with new standards, such as 802.11n. Thus, the scanning time is long, which causes the system to stay in a degraded performance state until the switch to a new channel can be made.
As a wireless radio in the access point can only transmit or receive on one channel, it cannot perform data communication on a single channel and scan the other channels at the same time. Hence, during the channel scanning, data communication must stop, and this leads to disruption of connectivity and service. This delay severely impacts network services, such as voice over IP (VoIP) or streaming video, provided via the wireless network.